A form of neuronal ceroid lipofuscinosis (NCL) characterized by onset during the second half of the first year of life and rapid mental and motor deterioration leading to loss of all psychomotor abilities. The disease is infantile neuronal ceroid lipofuscinosis (MONDO_0019261). Also known as: Classic Infantile CLN1 Disease, Hagberg-Santavuori disease, INCL, Santavuori disease, Santavuori-Haltia disease, infantile NCL.